In general, a printed circuit board (PCB) refers to a wiring board on which electronic parts are mounted to electrically connect parts or signal lines.
Furthermore, the PCB is completed by compressing a copper foil against one side or both sides of an insulating plate, such as phenol resin and epoxy resin, forming a conductive pattern according to a circuit, configuring the circuit by removing the copper foil through the corrosion of an unnecessary portion, perforating a via for connecting electronic parts into the PCB, performing plating, and coating a top surface and bottom surface with photo solder resist (PSR) ink.
Furthermore, the LED is chiefly used in the liquid crystal display device (LCD) of a mobile phone, an electronic display board, and a dashboard for a vehicle because it has low consumption power, has long lifespan and does not generate a contaminant, such as environment pollution.
As the LED recently has a wider application, it is applied to common lamps or the headlight of a vehicle in addition to the indoor light or signboard of a vehicle and the backlight unit (BLU) of an LCD device.
In particular, an LED lamp module (M) applied to the headlight of a vehicle is configured to include a reflector, for reflecting light generated by an LED, a board for controlling the mounted LED through the supply of power, a heat sink for externally discharging heat generated by the LED, and a back cover on which the heat sink is mounted.
Furthermore, recently, there was pointed out that a board used for various parts, including the LED, has a low heat-dissipation effect. In order to solve this problem, a metal board adopting metal materials, such as aluminum or a copper alloy, (hereinafter a metal board) has been in the spotlight in the market.
In particular, recently, in relation to the demands for a metal board on which an LED is mounted, there emerges a demand for a metal board on which an LED is mounted which is capable of being mechanically formed, such as curving or pressing.
The technology of a conventional metal PCB assembly for a vehicle lamp related to such a technology is proposed in Korean Patent No. 1589017. In its configuration, as in FIG. 1, the metal PCB assembly 10 for a vehicle lamp includes a metal PCB 14; at least one unit pattern (not shown) disposed on the metal PCB 14, having three faces cut and one face connected to the metal PCB 14, and protruded from the metal PCB 14 at a specific angle in the inclined state; and a projected matter coupled to the metal PCB 14 and enabling a support part protruded toward a horizontal surface to support the unit pattern and maintain a specific angle. The assembly of the metal PCB 14 includes a bending groove 24 of a specific depth formed at the bottom of the metal board 22 and bends each unit pattern on which each LED is mounted by forward pushing the unit pattern based on the bending groove, thereby fabricating the metal PCB assembly 10 having a stepped shape with a small power.
In this case, the external three faces 20a, 20b and 20c of the unit pattern are also cut. Since one face 20d of the unit pattern has been integrated and connected to the metal PCB 14, the unit pattern is not fully separated from the metal PCB 14 and is inclined at a specific angle and protruded with one side connected to the metal PCB 14.
However, such a metal PCB assembly for a vehicle lamp has disadvantages in that it has a configuration in which the unit pattern is bent, the unit patterns must be spaced apart in forming the external three faces for bending and it is difficult to mount the LED chips at a desired degree of integration.
Furthermore, a technology for an LED lamp module is proposed by Korean Patent No. 1344361. As in FIG. 2, the LED lamp module includes a reflector bar 100 for reflecting light generated by LEDs and a PCB 200 detachably mounted on the back surface of the reflector bar 100 in a one-touch manner, for controlling the LEDs. The PCB 200 is equipped with heat sinks 210 corresponding to the respective reflectors 110. The PCB 200 is detachably mounted on the reflector bar 100 through the heat sinks 210.
Furthermore, at least two stoppers 111 and guide protrusions 112 are formed at each location of the back surface of the reflector 110. The stoppers 111 are coupled to the heat sink 210 in a one-touch manner, and the guide protrusions 112 function to provide guidance so that the PCB 200 and the heat sink 210 are located at their regular position.
However, such an LED lamp module has disadvantages in that heat-dissipation efficiency is low because the area of the heat sink 210 is limited and an assembly time and cost are increased because the separate heat sinks 210 are connected to the printed circuit board 200.
In addition, a conventional technology for a metal PCB assembly for a vehicle lamp is proposed by Korean Patent No. 1589017. As shown in FIG. 3, the metal PCB assembly 30 for a vehicle lamp includes a metal PCB 34; at least one unit pattern (not shown) disposed on the metal PCB 34, having three faces cut and one face connected to the metal PCB 34, and inclined at a specific angle to the metal PCB 34 and protruded; and a projected matter coupled to the metal PCB 34, wherein a support part protruded from a horizontal surface supports the unit pattern to maintain a specific angle. The metal PCB 34 assembly includes a bending groove of a specific depth at the bottom of the metal board 34, and the unit pattern on which each LED is mounted is bent by forward pushing it based on the bending groove, thereby fabricating the metal PCB assembly 30 having a stepped shape with a small power.
In this case, the external three faces of the unit pattern are cut, and one face of the unit pattern has been integrated with the metal PCB 34. Accordingly, the unit pattern is not fully separated from the metal PCB 34, but is inclined and protruded at a specific angle with one side connected.
However, such a metal PCB assembly for a vehicle lamp has disadvantages in that it has a configuration in which the unit patterns are bent, the unit patterns must be spaced apart from each other in forming the external three faces for bending and it is difficult to mount the LED chips at a desired degree of integration.
A conventional technology for a metal printed circuit board has been proposed as a method of manufacturing a metal printed circuit board in Korean Patent No. 1435451. As shown in FIG. 4, the metal printed circuit board includes an insulating layer 320, a circuit layer 310 formed on the top surface of the insulating layer 320, and a metal layer 330 formed on the bottom surface of the insulating layer 320.
Furthermore, a linear groove 332 has been processed at the bottom surface of the metal layer 330. The metal printed circuit board is bent and formed along the groove, and an LED chip 300 is mounted on the metal printed circuit board, thereby providing the metal printed circuit board including the circuit layer 310, the insulating layer 320 and the metal layer 330.
Furthermore, the metal printed circuit board is bent and formed in the state in which the direct type LED chip 300 has been mounted and a light guide plate 340 is disposed on the same surface as the direct type LED chip 300 to perform a backlight unit function.
However, such a metal printed circuit board has a disadvantage in that it has a configuration also serving as a light guide plate and cannot be easily applied to a polygonal or multi-directional structure and it has a difficulty in its application because the LED chips radiate light in different directions when the metal printed circuit board is bent.